Heat and heat dissipation of cylindrical roller bearings

The operating temperature of cylindrical roller bearings depends on many factors, including the amount of heat generated by all related heat sources, the heat flow rate between the heat sources, and the heat dissipation capacity of the system. Heat sources include bearings, seals, gears, clutches and oil supply, etc. Heat dissipation depends on many factors, including the material and design of the shaft and bearing housing, the circulation of lubricating oil, and the external environmental conditions. These factors will be introduced separately in subsequent chapters. Under normal working conditions of heating, most of the torque and heat of the bearing model comes from the dynamic loss of the elastic fluid at the contact part of the roller/bearing ring. Heat is a product of bearing torque and speed. Use the formula below to calculate the calorific value. Qgen u003d k4n M tapered bearings can use the following formula to calculate the torque. M u003d k1G1 (nμ)0.62 (Peq) 0.3 where: k1 u003d bearing torque constant u003d 2.56 x 10-6 (M unit is Newton-meter) k4 u003d 0.105 (Qgen unit is W, M unit is Newton— M) For non-tapered bearings, the calculation method of torque is given in the following chapters. Heat dissipation: How to determine the heat flow of a bearing in a special application is a complex problem. Generally speaking, it can be considered that the factors that affect the heat dissipation rate include: 1. The temperature gradient from the bearing to the bearing seat. This factor is affected by the size of the bearing housing and external cooling devices (such as fans, water cooling devices, etc.). 2. The temperature gradient from the bearing to the shaft. All other heat sources, such as gears and other bearings and adjacent parts, will affect the temperature of the shaft. 3. The heat taken away by the circulating oil lubrication system. To some extent, factors 1 and 2 can be different depending on the application. The heat dissipation mode includes heat conduction in the system, convection on the inner and outer surfaces, and heat radiation between adjacent structures. In many applications, heat dissipation can be divided into two parts: the heat carried away by the circulating oil and the heat dissipated through the structure. The heat taken away by the circulating oil system to dissipate the lubricating oil is easier to control. In a splash lubrication system, a cooling coil can be used to control the temperature of the lubricating oil. The heat taken away by the lubricating oil in the circulating oil lubrication system can be calculated by the following formula. Qoil u003d k6 Cpρf (θo-θi) where: k6 u003d 1.67 x 10-5 (the unit of Qoil is W) u003d 1.67 x 10-2 (the unit of Qoil is BTU/min) If the circulating lubricant is mineral oil, take it away The amount of heat can be calculated with the following formula: Qoil u003d k5 f (θo-θi) The following coefficients are applicable to the heat and heat dissipation formulas listed on this page. Among them: k5 u003d 28 (The unit of Qoil is W, the unit of f is L/min, and the unit of θ is °C).